Resistance of isoniazid dependent and resistant strains of Mycobacterium tuberculosis to anti-tuberculosis drugs

Objective To investigate the resistance of isoniazid（H） dependent and resistant Mycobacterium tuberculosis（M.tuberculosis） strains to anti-tuberculosis drugs and its mechanism.Methods M.tuberculosis strains were isolated from sputum specimens and cultured with double-phase Kuang’s agar medium.Rifampin resistant and dependent M.tuberculosis strains were detected.Results The resistance rate of M.tuberculosis strains to 8 anti-tuberculosis drugs was higher in H-dependent M.tuberculosis strains than in H-resistant M.tuberculosis strains.The ratios of multidrug-resistant（MDR） strains and extensively drug-resistant（XDR） strains were 94.4% and 13.9%,respectively,in H-dependent M.tuberculosis strains,which were higher than those in H-resistant M.tuberculosis strains.Conclusion The MDR strains account for 94.4% of all H-dependent Mycobacterium tuberculosis strains with a high resistance rate against first-and second-line anti-tuberculosis drugs and are easy to evolve into XDR strains.Thus,sharp vigilance and attention should be paid to them.